A stretchable device includes strain gauges and electrical wiring. Each strain gauge includes a first strain gauge and a second strain gauge. The first strain gauge and the second strain gauge are coupled to each other. The electrical wiring includes a first potential line, a second potential line, a coupling line coupling the first potential line to the second potential line, a first signal line, and a second signal line. The first signal line detects a third potential at a first coupling point. The second signal line detects a fourth potential at a midpoint of the coupling line. One of the first strain gauge and the second strain gauge is an inner peripheral strain gauge. The other thereof is an outer peripheral strain gauge. The amount of change in resistance of each strain gauge is detected based on a potential difference between the third potential and the fourth potential.